import { toByteArray } from 'base64-js'
import Compressor from 'compressorjs'

// 根据base64转为file
export function  base64ToFile(base64String, fileName) {
    const arr = base64String.split(',')
    const mime = arr[0].match(/:(.*?);/)[1]
    const bstr = toByteArray(arr[1])
    const file = new File([new Uint8Array(bstr)], fileName, { type: mime })
    return file
}

// 压缩file(compressFileSize:压缩到指定大小，比如2M则compressFileSize为2,不指定则默认只压缩一次)
export function  compressFile(file,compressFileSize) {
    console.log('压缩前大小：',file.size);
    let resultFile
    new Compressor(file, {
        quality: 0.6, // 压缩质量
        success(result) {
            // 压缩成功后，将压缩后的图片转为base64并返回
            const reader = new FileReader()
            reader.readAsDataURL(result)
            reader.onload = () => {
                const base64 = reader.result
                let newFile = self.base64ToFile(base64, 'text')
                console.log('压缩后大小：', newFile.size)
                if(compressFileSize && compressFileSize >0){
                    if (newFile.size > compressFileSize * 1024 * 1024) {
                        compressFile(newFile)
                    } else {
                        resultFile = newFile
                    }
                } else {
                    resultFile = newFile
                }
            }
        },
        error(err) {
            console.log(err.message)
        }
    })
    return resultFile
}
